// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

class Class1 {
  Class1? get property => null;

  void set property(Class1? value) {}

  Class1 get property1 => new Class1();

  Class2 get property2 => new Class2();
}

extension Extension1 on Class1 {
  Class1? get nullable1 => property1;

  void set nullable1(Class1? value) {
    property = value;
  }

  Class1 nonNullable1Method() => nonNullable1;

  Class1? operator [](Class1? key) => nullable1;

  void operator []=(Class1? key, Class1? value) {
    property = value;
  }

  Class1? operator +(int value) => nullable1;

  Class1? operator -() => nullable1;

  Class1 get nonNullable1 => property1;

  Class2 get nonNullable2 => property2;
}

class Class2 {
  Class2 get property => this;

  void set property(Class2 value) {}
}

extension Extension2 on Class2 {
  Class2 nonNullable2Method() => nonNullable2;

  Class2 operator [](Class2? key) => property;

  void operator []=(Class2? key, Class2? value) => property;

  Class2 operator +(int value) => property;

  Class2 operator -() => property;

  Class2 get nonNullable2 => property;

  void set nonNullable2(Class2 value) {
    property = value;
  }
}

class Class3 {
  Class2? get property => null;
}

extension Extension3 on Class3 {
  Class2? operator [](Class3? key) => property;
}

main() {
  propertyAccess(null);
  indexAccess(null, null, null);
  operatorAccess(null, null);
  ifNull(null);
}

void propertyAccess(Class1? n1) {
  Class1? nullable1 = n1;

  Extension1(n1)?.nullable1;
  Extension1(n1)?.nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1 = new Class1();
  Extension1(n1)?.nonNullable1Method();

  Extension1(n1)?.nonNullable1.nullable1;
  Extension1(n1)?.nullable1?.nullable1;
  Extension1(n1)?.nonNullable1.nullable1?.nullable1;
  Extension1(n1)?.nonNullable1.nullable1 = new Class1();
  Extension1(n1)?.nullable1?.nullable1 = new Class1();
  Extension1(n1)?.nonNullable1.nullable1?.nullable1 = new Class1();
  (Extension1(n1)?.nullable1)?.nullable1;
  throws(() => (Extension1(n1)?.nullable1 = new Class1()).nullable1);
  throws(() => (Extension1(n1)?.nonNullable1Method()).nullable1);
  nullable1 = Extension1(n1)?.nonNullable1.nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1?.nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nonNullable1.nullable1?.nullable1 = new Class1();
  Extension1(n1)?.nullable1?.nonNullable1Method();
  Extension1(n1)?.nullable1 = new Class1().nullable1;
  nullable1 = Extension1(n1)?.nullable1 = new Class1().nullable1;
  Extension1(n1)?.nullable1 = new Class1().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1 = new Class1().nullable1 = new Class1();
  Extension1(n1)?.nullable1 = new Class1().nonNullable1Method();
  nullable1 = Extension1(n1)?.nullable1 = new Class1().nonNullable1Method();
  Extension1(n1)?.nonNullable1Method().nullable1;
  Extension1(n1)?.nonNullable1Method().nullable1 = new Class1();
  Extension1(n1)?.nonNullable1Method().nonNullable1Method();

  Extension1(n1)?.nonNullable1.nonNullable1.nullable1;
  Extension1(n1)?.nonNullable1.nonNullable1.nullable1 = new Class1();
  nullable1 =
      Extension1(n1)?.nonNullable1.nonNullable1.nullable1 = new Class1();
  Extension1(n1)?.nonNullable1.nullable1?.nonNullable1Method();
  Extension1(n1)?.nullable1 = new Class1().nonNullable1.nullable1;
  nullable1 = Extension1(n1)?.nullable1 = new Class1().nonNullable1.nullable1;
  Extension1(n1)?.nullable1 =
      new Class1().nonNullable1.nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nonNullable1.nullable1 = new Class1();
  Extension1(n1)?.nullable1 = new Class1().nonNullable1.nonNullable1Method();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nonNullable1.nonNullable1Method();
  Extension1(n1)?.nonNullable1Method().nonNullable1.nullable1;
  Extension1(n1)?.nonNullable1Method().nonNullable1.nullable1 = new Class1();
  Extension1(n1)?.nonNullable1Method().nonNullable1.nonNullable1Method();

  Extension1(n1)?.nonNullable1.nullable1 = new Class1().nullable1;
  nullable1 = Extension1(n1)?.nonNullable1.nullable1 = new Class1().nullable1;
  Extension1(n1)?.nonNullable1.nullable1 =
      new Class1().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nonNullable1.nullable1 =
      new Class1().nullable1 = new Class1();
  Extension1(n1)?.nonNullable1.nullable1 = new Class1().nonNullable1Method();
  nullable1 = Extension1(n1)?.nonNullable1.nullable1 =
      new Class1().nonNullable1Method();
  Extension1(n1)?.nullable1 = new Class1().nullable1 = new Class1().nullable1;
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nullable1 = new Class1().nullable1;
  Extension1(n1)?.nullable1 =
      new Class1().nullable1 = new Class1().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nullable1 = new Class1().nullable1 = new Class1();
  Extension1(n1)?.nullable1 =
      new Class1().nullable1 = new Class1().nonNullable1Method();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nullable1 = new Class1().nonNullable1Method();
  Extension1(n1)?.nonNullable1Method().nullable1 = new Class1().nullable1;
  nullable1 =
      Extension1(n1)?.nonNullable1Method().nullable1 = new Class1().nullable1;
  Extension1(n1)?.nonNullable1Method().nullable1 =
      new Class1().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nonNullable1Method().nullable1 =
      new Class1().nullable1 = new Class1();
  Extension1(n1)?.nonNullable1Method().nullable1 =
      new Class1().nonNullable1Method();
  nullable1 = Extension1(n1)?.nonNullable1Method().nullable1 =
      new Class1().nonNullable1Method();

  Extension1(n1)?.nonNullable1.nonNullable1Method().nullable1;
  Extension1(n1)?.nonNullable1.nonNullable1Method().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nonNullable1.nonNullable1Method().nullable1 =
      new Class1();
  Extension1(n1)?.nonNullable1.nonNullable1Method().nonNullable1Method();
  Extension1(n1)?.nullable1 = new Class1().nonNullable1Method().nullable1;
  nullable1 =
      Extension1(n1)?.nullable1 = new Class1().nonNullable1Method().nullable1;
  Extension1(n1)?.nullable1 =
      new Class1().nonNullable1Method().nullable1 = new Class1();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nonNullable1Method().nullable1 = new Class1();
  Extension1(n1)?.nullable1 =
      new Class1().nonNullable1Method().nonNullable1Method();
  nullable1 = Extension1(n1)?.nullable1 =
      new Class1().nonNullable1Method().nonNullable1Method();
  Extension1(n1)?.nonNullable1Method().nonNullable1Method().nullable1;
  Extension1(n1)?.nonNullable1Method().nonNullable1Method().nullable1 =
      new Class1();
  Extension1(n1)
      ?.nonNullable1Method()
      .nonNullable1Method()
      .nonNullable1Method();

  Extension1(n1)?.nonNullable1Method()?.nonNullable1Method();
}

void indexAccess(Class1? n1, Class2? n2, Class3? n3) {
  Class1? nullable1 = n1;
  Class2? nullable2 = n2;
  Class3? nullable3 = n3;

  Extension1(n1)?.[nullable1];
  Extension1(n1)?.[nullable1] = new Class1();
  Extension1(n1)?.[nullable1]?.nonNullable1Method();
  Extension1(n1)?.nonNullable1[nullable1];
  Extension1(n1)?.nonNullable1[nullable1] = new Class1();
  nullable1 = Extension1(n1)?.nonNullable1[nullable1] = new Class1();
  Extension1(n1)?.nonNullable1[nullable1]?.nonNullable1Method();
  Extension1(n1)?.nonNullable2[nullable2] += 0;
  nullable2 = Extension1(n1)?.nonNullable2[nullable2] += 0;
  Extension1(n1)?.[nullable1] ??= nullable1;
  nullable1 = Extension1(n1)?.[nullable1] ??= nullable1;
  Extension2(n2)?.[nullable2] += 0;
  nullable2 = Extension2(n2)?.[nullable2] += 0;
  Extension2(n2)?.[nullable2] += 0;
  nullable2 = Extension2(n2)?.[nullable2] += 0;
  Extension2(n2)?.[nullable2]++;
  nullable2 = Extension2(n2)?.[nullable2]++;
  ++Extension2(n2)?.[nullable2];
  nullable2 = ++Extension2(n2)?.[nullable2];
  Extension1(n1)?.nonNullable2[nullable2]++;
  nullable2 = Extension1(n1)?.nonNullable2[nullable2]++;
  ++Extension1(n1)?.nonNullable2[nullable2];
  nullable2 = ++Extension1(n1)?.nonNullable2[nullable2];

  Extension1(n1)?.nonNullable2[nullable2][nullable2];
  Extension1(n1)?.nonNullable2[nullable2][nullable2] = new Class2();
  nullable2 = Extension1(n1)?.nonNullable2[nullable2][nullable2] = new Class2();
  Extension1(n1)?.nonNullable2[nullable2][nullable2]?.nonNullable2Method();
  Extension1(n1)?.nonNullable2[nullable2][nullable2] += 0;
  nullable2 = Extension1(n1)?.nonNullable2[nullable2][nullable2] += 0;
  Extension1(n1)?.nonNullable2[nullable2][nullable2]++;
  nullable2 = Extension1(n1)?.nonNullable2[nullable2][nullable2]++;
  ++Extension1(n1)?.nonNullable2[nullable2][nullable2];
  nullable2 = ++Extension1(n1)?.nonNullable2[nullable2][nullable2];

  Extension1(n1)?.[nullable1]?.[nullable1];
  Extension1(n1)?.[nullable1]?.[nullable1] = new Class1();
  nullable1 = Extension1(n1)?.[nullable1]?.[nullable1] = new Class1();
  Extension1(n1)?.[nullable1]?.[nullable1]?.nonNullable1Method();
  nullable1 = Extension1(n1)?.[nullable1]?.[nullable1]?.nonNullable1Method();
  Extension1(n1)?.[nullable1]?.[nullable1] ??= nullable1;
  nullable1 = Extension1(n1)?.[nullable1]?.[nullable1] ??= nullable1;
  Extension3(n3)?.[nullable3]?.[nullable2] += 0;
  nullable2 = Extension3(n3)?.[nullable3]?.[nullable2] += 0;
  Extension3(n3)?.[nullable3]?.[nullable2]++;
  nullable2 = Extension3(n3)?.[nullable3]?.[nullable2]++;
  ++Extension3(n3)?.[nullable3]?.[nullable2];
  nullable2 = ++Extension3(n3)?.[nullable3]?.[nullable2];
}

void operatorAccess(Class1? n1, Class2? n2) {
  Class2? nullable2 = n2;

  throws(() => Extension1(n1)?.nonNullable1 + 0);
  throws(() => -Extension1(n1)?.nonNullable1);
  Extension2(n2)?.nonNullable2 += 0;
  nullable2 = Extension2(n2)?.nonNullable2 += 0;
  Extension2(n2)?.nonNullable2.nonNullable2 += 0;
  nullable2 = Extension2(n2)?.nonNullable2.nonNullable2 += 0;
  Extension2(n2)?.nonNullable2++;
  nullable2 = Extension2(n2)?.nonNullable2++;
  ++Extension2(n2)?.nonNullable2;
  nullable2 = ++Extension2(n2)?.nonNullable2;
}

void ifNull(Class1? n1) {
  Class1? nullable1 = n1;

  n1?.nullable1 ??= n1;
  n1 = n1?.nullable1 ??= n1;
  n1?.nonNullable1.nullable1 ??= n1;
  n1 = n1?.nonNullable1.nullable1 ??= n1;
  n1?.nonNullable1[n1] ??= n1;
  n1 = n1?.nonNullable1[n1] ??= n1;
}

void throws(void Function() f) {
  try {
    f();
  } catch (_) {
    return;
  }
  throw 'Expected exception.';
}